Overdraft detection for crawl carry



y 1956 G. v. HALL ET AL OVERDRAFT DETECTION FOR CRAWL CARRY 3 Sheets-5heet 1 Filed Dec. 5, 1952 TO UTILIZATION FIG.2

DEVICES FIG.6

y 8, 956 G. v. HALL ET AL OVERDRAFT DETECTION FOR CRAWL CARRY 3 Sheets-Sheet 2 Filed Dec. 3, 1952 A L RAL Y 0 W E m m E vfl /fm mRE T CL E n Gw/d/ Y B y 8, 1956 G. v. HALL ET AL OVERDRAFT DETECTION FOR CRAWL CARRY 3 Sheets-Sheet 3 Filed Dec. 3, 1952 FIC5.8

BY WALTER S. OLIWA ATTORNEY INVENTORS GEORGE V. HALL United States Patent 2,744,681 OVERDRAFT DETECTIGN FOR CRAWL CARRY George V. Hall, Orange, and Walter S.

N. J., assignors to pany, Orange,

Claims. (Cl. 235- 1) This application is a continuation of application No. 272,594 filed on February 20, 1952, and now abandoned.

The invention relates to registers having tens transfer mechanism of the crawl type, and more particularly to means whereby change of such a register to or from a positive, negative, or zero condition may be detected without the necessity of moving the register wheels to aligned or reading position.

It is well known in the art that a change in the arithmetical sign of a calculating machine register may be utilized to control certain of the machine operations. For example, in the performance of a division calculation by the well known subtract, add, shift method, the registering mechanism is cycled subtractively until the dividend is reduced to a negative value, and thereupon the subtractive registration is terminated. A plus corrective cycle of the registering mechanism is then instituted after which the register carriage is shifted and the program continued.

Upon change of the sign in a register having jump tens transfer mechanisms, the tens transfer from lower to higher order wheels is extended toward the left as far as such transfer mechanism is provided. A signal upon change of the sign of the register, therefore, may be taken from the highest order wheel aligned with the keyboard upon passage of the wheel from O to 9 or from 9 to 0 by relatively simple sign detecting mechanism.

In registers having crawl tens transfer mechanism, the continuously engaged transfer gearing between the wheels and the continuously driven differential actuators adapts such registers for a higher speed of operation than is practical with intermittently driven registers of the jump transfer type. However, in crawl transfer registers, appreciable transfer movement is imparted only to the next higher order wheel from a lower order wheel and due to the ratio of the transfer gearing and to lost motion substantially no movement at all is imparted to the still higher order wheels. Therefore, should actuation of a lower order significant wheel be effective to change the sign of the register, a signal may be taken from the highest order wheel only if the wheels are moved to aligned or reading position.

In the use of addding, listing bookkeeping machines having registers of the crawl transfer type, it is obviously desirable that the operator should know at all times whether a particular register is in a positive, zero, or negative condition and thus avoid the necessity of a total taking operation to determine such condition.

In view of the foregoing, the invention provides an optical system adjustable, upon change of the sign of a crawl" tens transfer register, to impinge a light ray upon a light responsive device such as a photoelectric cell. An electric signaling circuit is energized under control of the photoelectric cell and, as hereinafter described, may be adapted to control the registering operations in a program of division or may be utilized to in- 70 dicate the arithmetical state of the register. Furthermore, the optical system may be adapted to impinge the light ray upon a second photoelectric cell upon movement of the register to zero registering position so that all of the conditions of the register may be indicated. The invention, however, will best be understood from the following description with reference to the accompanying drawings in which:

Fig. 1 is an exploded perspective view of a series of the crawl tens transfer register wheels showing the optical and photoelectric devices of one form of the invention associated therewith;

Fig. 2 is an enlarged detail view, partly in section, of the register wheels and optical devices of Fig. 1;

Fig. 3 is a schematic view of the optical and photoelectric devices of Fig. 1 showing the sign signaling circuit associated therewith as adapted to control a program of division;

Fig. 4 is a fragmentary elevation of the register carriage showing means whereby a light ray may be established for association with the electro-optical system;

Fig. 5 is a schematic view of an alternate form of the invention;

Fig. 6 is a detail elevation of one of the optical devices of Fig. 5;

Fig. 7 is a fragmentary left side view of a calculating machine embodying the invention with the carriage for the crawl tens transfer register in section; and,

Fig. 8 is a fragmentary detail view of a portion of the registration control mechanism shown in Fig. 7.

The electric optical sign signifying devices The register comprises a series of ordinally arranged numeral wheels 1 (Figs. 1, 2 and 4). Any well known type of craw tens transfer mechanism may be interposed between the wheels. Such a mechanism may be of the orbital type fully disclosed in Gardner Patent No. 1,828,180 and is designated generally by the reference numeral 2 (Fig. 2).

Each of the register wheels 1 has a gear 3 fixed to its left side face. In the form of the invention which will be described first and which is illustrated in Figs. 1, 2 and 3, each gear 3 drives a gear 4 of like size rotatably mounted on a shaft 5 which is parallel to the axes of wheels 1. Gears 4 will therefore be driven at a one to one ratio with wheels 1 and are ordinally associated therewith. The highest order gear 4 or a series of the gears 4 including the highest order gear is adapted to control a light ray 9 to impinge upon a photoelectric cell 6 upon change of sign of the register. Each gear 4, therefore, constitutes an optical device, and a series of the gears an optical system. The optical arrangement comprises an opening 10 in each gear 4 and a reflector 11 on the left side face of each gear. The open- I ings 10 and relfectors 11 are located on an are a slight distance inwardly of the roots of the teeth of each gear 4, and each opening and reflector has like dimensions and like location on gears 4 with relation to the positions of the associated register wheels 1.

Any well known means may be employed at the left of the highest order gear 4 to establish light ray 9. As shown in Fig. 4, a light source comprising a light bulb 7 may be mounted in a suitable housing at the left end of register carriage 8. Current for bulb 7 may be transmitted in any shifted position of the carriage through brushes (not shown) from any suitable power source. A collimating lens 12 directs the light ray 9 in a path parallel to the axes of gears 4 and located radially outward from the axes a distance equal to that of the arcs on which openings 10 and reflectors 11 are located.

Schematic Fig. 3 best illustrates the positions of openings 10 and reflectors 11 with relation to the path of light ray 9 as determined by the registering positions of wheels 1, which positions are indicated by the alignment of the digit markings on gears 4 with arrow 13 at the top of the schematic. When the numeral wheels are in substantially zero registering position, openings 10 are fully aligned wiath light ray Q which is approximately the size of the openings. If a wheel is moved either additively or subtractively substantially one-half a digit space from zero position, the opening 10 of the associated gear 4 will be removed entirely from the path of ray 9. As a wheel is moved negatively from zero position, the reflector 11 of the associated gear 4 will be moved into the path of ray 9 and extends arcuately so that it will remain in said path until the wheel has been moved approximately to its 5 registering position. In all other registering positions of a wheel 1, a non-reflecting surface of the associated gear 4 will be in the path of light ray 9. The photoelectric cell 6 is of tubular shape and extends the length of the register at one side of gears 4 and parallel to their axes. The reflectors 11 are inclined to the faces of gears 4 at such an angle that if light ray 9 is impinged upon any one of the reflectors, it will be reflected to the side to impinge upon photoelectric cell 6. Upon change of the sign of the register, light ray 9 is caused to impinge upon one of the reflectors as hereinafter described.

The highest order wheel 1 of the register comprises a dummy or overflow control wheel in which no digital registration is effected but only registration by the crawl transfer from the adjacent order wheel, and which is necessary to determine if the adjacent order wheel has arrived at a given registering position by positive or negative registration. Digtal registration may be effected in all of the other wheels by drive to the digital input gears 14 (Fig. 2) from differential actuators of any well known construction such as the reversible rotary type by which registration is eifected continuously throughout a complete cycle of operation, the wheels being driven at speeds proportional to the digital values being registered.

First, it will be assumed that the wheel adjacent the overflow wheel is moved in a positive direction to register any digital value of from 1 to 5. If the value registered is less than 5, the crawl transfer will not have moved opening 10 of gear 4 of the overflow wheel entirely from the path of light ray 9. Therefore, portions of the ray will be impinged upon the overflow gear 4 and the adjacent order gear respectively. The reflectors 11, however, of these two gears will be out of the path of the light ray and therefore the ray will not be impinged upon photoelectric cell 6. If the positive value registered is 5, the opening of the overflow gear 4, theoretically, will be moved by the crawl carry from the path of the light ray which, in its entirety, will then be impinged upon the non-reflective surface of the gear. If, however, due to lost motion, the opening is not entirely moved from the path of the light ra portions of the ray respectively will be impinged upon the non-reflective surface of both gears 4 as in the instance of the registration of less than 5. Next, it will be assumed that the wheel adjacent the overflow wheel is moved in a positive direction to register a value of from 6 to 9. The reflector 11 of gear 4 of the adjacent order wheel will be moved into the path of light ray 9, but opening 1% of the overflow gear 4 will have been moved by the craw transfer out of the path of ray 9. Therefore, the ray will be impinged upon the non-reflective surface of the overflow gear and will be blocked from impingement upon the reflector of the adjacent order gear.

The operation of the optical system will now be considered upon movement of the wheel adjacent the overflow wheel to a negative value. Upon movement of the wheel negatively to any value of from 9 to 6, the reflector 11 of the associated gear 4 will be moved into the path of light ray 9. The opening 16 of overflow gear 4 will not have been moved entirely from the path of the light ray by the rawl carry and the reflector of the overflow gear will have been partially moved into the path of the ray. Therefore, portions of the ray will be impinged upon both reflectors respectively and the ray, therefore, will be reflected upon photoelectric cell 6. If the wheel adjacent the overflow wheel is moved negatively to the 5 position or beyond, the reflector 11 of the associated gear 4 will be moved out of the path of light ray 9. The reflector of the overflow gear 4, however, will have been moved by the crawl carry into the path of the light ray and the ray will be reflected upon the photoelectric cell. It will be observed correctly that, in the negative movement of the wheel adjacent the overflow wheel to the 5 position or beyond, the light ray normally will be impinged upon the photoelectric cell as the wheel is moved negatively from its zero position. However, in a program of division to be described, means is provided to prevent response of the photoelectric cell until near the end of a cycle of registration. At this time, the wheel will have passed into the 5 to 1 range and therefore the overflow wheel alone must be effective to cause impingement of the light ray upon the cell.

If a series of wheels including the overflow wheel are moved to substantially their Zero positions, the light ray will be permitted passage through the associated gears 4. Therefore, the gears 4 of the next two adjacent lower order wheels which are displaced from zero position will control the light ray in the same manner as discribed in connection with the overflow wheel and the adjacent order wheel. It will be noted that the higher of the two lower order wheels at times alone must be eflective to control the light ray for the reason described in connection with the overflow wheel and its adjacent order wheel, and for the additional reason that one or more of the wheels which are moved to substantially their zero positions to permit passage of the light ray may not be moved thereto until near the end of a cycle of registration, at which time the lower of the two lower order wheels will have passed into its ineifective range. Also, it will be noted that there is considerable overlapping in the control of two adjacent order wheels, thereby providing a definite control even though there may be considerable lost motion in the mechanism. Furthermore, it will be apparent that reflectors 11 may be so located on gears 4 that, upon change of the register from negative to positive instead of from positive to negative, the light ray will be impinged upon the photoelectric cell.

The photoelectric cell 6 is shown in Fig. 3 as associated with an amplifier to operate a relay 17 when the cell is energized by the right ray. The photoelectric cell is shown as connected to amplifier 15 through sliding connections 19 and 2%) with conductors 33 and 34, and a switch 23. However, relay 17, switch 23 and the sliding connections are essential only in connection with the control of a program of division hereinafter described. Therefore, another electro-responsive indicating device, i. e., a light, a bell, etc. may be substituted for relay 17. Also the photoelectric cell may have direct connection with amplifier 15.

Figs. 5 and 6 illustrate an alternate form of the invention. The gears 35 are driven by gears 3 and are related to the positions of the numeral wheels in the same manner as described in connection with gears 4. In lieu of the inclined reflectors 11, each gear 35 has a flat reflecting surface 26 on its left side face. This surface 26 has the same arcuate range as the reflectors ill. Also each gear 35 has an opening 36 located in the same relation to the zero position as the openings 10. A photoelectric cell 28 is located adjacent the light source 7. The light is directed at an angle to the left faces of gears 35. Upon change of the register from positive to negative, the light ray will be impinged upon the reflecting surface 26 of one of the gears as described in connection with reflectors 11. The light ray, however, instead of being reflected to one side will be reflected back to impinge on cell 28 if the control is from the overflow wheel. if the control is from a lower order wheel as shown in Fig. 5, openings 36 in the higher order wheels will permit back reflection of the ray to impinge on cell 28. It will be noted that the light fay will be reflected back at a slightly different angle from the successive order gears 35. It will be readily seen, however, that cell 28 may be constructed and located so that the reflected ray will always fall upon its light sensitive element. The cell 28 may be connected to an amplifier to control a signaling device as heretofore described.

A second cell 30 (Fig. 5) may be located to the right of the lowest order gear 35. If all of the register wheels "are moved to zero position, the light ray will be permitted passage through all of the openings 36 to impinge on cell 30. A suitable indicating device may be controlled by cell 30 and thus it may be determined when the register is ina zero condition. This arrangement is also ob viously adaptable for use in conjunction with the devices described in connection with Figs. 1, 2 and 3.

Control of the division program The control of a division program is herein disclosed to illustrate one practical application of the invention. A The partially illustrated calculating machine, including division control mechanism (Fig. 7), operates substantially in accordance with the disclosure of Patent No. 2,531,207, issued to Herman Gang as modified by the devices of the present invention. Only the parts of the mechanism which are correlatively operable with the devices of the invention are described and illustrated and those parts are herein given the same reference numerals as those applied to the equivalent parts in the patent. Reference is made to this patent for a complete disclosure of the calculating machine and its operation in connection with a program of division.

The product-dividend register of the above noted patent is provided with tens transfer mechanism of the jump type. Division is effected by the well known subtract, add, shift method in which the divisor set on the keyboard (Fig. 7) is subtracted once more than it is contained in the corresponding portion of the dividend registered in the product dividend register. A negative numeral wheel reading is therefore obtained and the tens transfer mechanism will successively move the register wheels from 0 to 9 as far toward the left as such transfer mechanism is provided. This transfer is utilized to trip the control devices to terminate the subtractive operation, whereupon the actuating means is reversed and a single positive registration will occur. The excessive subtraction will therefore be corrected and the count corrected in "wheels 18 (Fig. 7) of the multiplier-quotient register,

thus leaving the correct quotient digit registered therein. The single positive registration will effect a second transfer to trip the control devices. The register carriage 8 will thereupon be shifted one order to the left and subtractive actuation initiated, thereby resuming the sequence of operation.

In accordance with the present invention, a productdividend register comprising the aforedescribed numeral wheels 1 of the crawl transfer type is substituted for the register of the aforenoted patent. Input gears 40 (Fig. 7) of reversible rotary differential actuators in the base of the machine efi'ect digital actuation to the numeral wheels through transmission trains comprising gears 41, 42, 43 and pinions 14 (Figs. 2 and 7) of the numeral wheels. The actuating mechanism may be of any well known type in which the registering operation is effected throughout each complete cycle of operation at speeds varying in proportion to the digital values being registered.

Means for moving wheels 1 to aligned or reading position operates substantially in accordance with the disclosure of Patent No. 2,089,682, issued to George C. Chase. This is accomplished by movement of transmission gears 43 about shaft 45 as a center to counteract the partial tens transfers. Each gear 43, except that of -the lowest order wheel, is mounted on an arm 46 which is pivot'ally mounted on shaft 45. Each arm 46 has at its free forward end a laterally extending lug adapted for engagement with a snail cam 47 (Fig. 7) attached to the next lower order wheel. During operation of the machine, the lugs of arms 46 are held upward a slight distance from the position shown in Fig. 7, as hereinafter described, to prevent interference with cams 47. At the end of an operation, arms 46 are spring moved downwardly until their lugs engage the cams of the next lower order wheels. Therefore, gears 43 will be moved around gears 42 imparting movement to pinions 14 to back out the partial tens transfers.

The form of the invention heretofore described and illustrated in Figs. 1, 2 and 3 is shown mounted in the shiftable register carriage 8, and the light source 7 and collimating lens 12 are mounted at the left end of the carriage as shown in Fig. 4.

The pair of conducting strips 33 and 34 are transversely mounted in the body of the machine adjacent the rear underside of register carriage 8. Strip 33 is directly connected to amplifier 15 (Fig. 3) and strip 34 is connected to the amplifier through switch 23. Conducting strips 33 and 34 respectively are engaged by brushes 19 and 29 which are connected with photoelectric cell 6. Thus, a path of current flow is provided between cell 6 and amplifier 15 with carriage 8 in any shifted position.

Upon depression of the divide key (not shown) link 722 (Fig. 7) will be moved toward the front of the machine, and pin 722' on the link will engage and rock latch arm 725 counterclockwise to release crank 726. Also upon depression of the divide key, switching means (not shown) may be closed to supply current to light source 7 (Fig. 4). Crank 726 and an arm 732 are fast on a shaft 616 and are spring biased in clockwise direction. Therefore, upon release of crank 726, the crank and arm 732 will be rocked clockwise and a link 733 attached to arm 732 will be moved toward the front of the machine. This movement of the parts will initiate subtractive operation of the driving means for the digital actuators and set various division controlling mechanisms, all as fully disclosed in the aforenoted Patent No. 2,531,207.

A link 730 is attached at its lower end to one arm of crank 726. The upper end of link 730 has slot and pin connection with the right arm of a lever 52 which is fulcrumed at 53 to the left side of the machine frame. Lever 52, therefore, normally is held in the counterclockwise position shown in Fig. 7. A bail 54, extending the length of carriage 8 is engaged by the left arm of lever 52 in any shifted position of the carriage. Upon the aforedescribed clockwise movement of crank 726, link 730 will be moved downwardly thereby rocking lever 52 clockwise and bail 54 counterclockwise. Thus, bail 54 will move all of arms 46 upward a slight distance from that shown in Fig. 7 and thereby move all of the register wheels 1 from aligned to crawl position.

When the registering mechanism has been cycled until the value in numeral wheels 1 has been reduced below zero, the light ray will be impinged upon cell 6 as described in connection with Figs. 1, 2 and 3. At this time, however, a circuit from the cell to amplifier 15 (Fig. 3) will not be completed because of switch 23 which is controlled as follows.

From a study of the range of reflectors 11 and openings 10 (Figs. 1 and 3), it has been determined that at about 15 before the end of a cycle of registration, light ray 9 will have been impinged upon cell 6 if there has been an overdraft. It is essential for high speed operation that the stopping means for the digital actuators be tripped before the actuators reach full cycle position; otherwise, the stopping means may fail to operate in time to prevent the actuators form effecting an extra cycle of operation. Therefore, when the digital actuators are approximately 15 from full cycle position in negative operation, a

v cycle of the actuators.

52 counterclockwise to normal.

cam 56 (Figs. 3 and 7), driven by a suitable gear train at a one to one ratio with the actuators, operates to close switch 23 as shown in Fig. 3 and, when the actuators have moved within several degrees of full cycle position, the cam permits switch 23 to reopen as shown in the full cycle position of the parts in Fig. 7. Therefore, if light ray 9 (Figs. 1 and 3) is impinged upon photoelectric cell 6, the closure of switch 23 will complete a circuit to amplifier thereby operating relay 17 to trip the stopping means as follows.

An arm 22 (Fig. 7) pivotally mounted at its lower end is reciprocally operated in time with the register actuators by a link 21. An arm 24 has common pivotal mounting with arm 22 and is spring urged to the position shown in Fig. 7. A pawl 25 which is spring biased counterclockwise is mounted on the upper end of arm 24 and is held in the clockwise position shown in Figs. 7 and 8 by a trigger 31 which spring biased clockwise. Upon operation of relay l7, trigger 31 will be moved counterclockwise thereby releasing pawl 25. Pawl 25 will, therefore, be moved counterclockwise and as the actuators pass through full cycle position, a shoulder 27 of arm 22 will engage pawl 25, thereby moving arm 24 against stop 29 as the actuators overrun beyond full cycle position. The movement of arm 24 against stop 29 will disconnect the actuator drive as described in Patent No. 2,531,207 and then will rebound in the revene direction carrying arm 22 therewith to move the actuators reversely or in a positive direction. The actuator drive will then be reengaged for a positive corrective cycle of operation.

When the actuators passed negatively through full cycle position switch 23 was opened, thereby deener izing relay 17. Trigger 31 was therefore spring moved clockwise and thus, upon rebound of arm 24 trigger 31 will engage pawl 25 to disconnect it from shoulder 27 of arm 22. Shoulder 27 of arm 22 will therefore be free to move beneath pawl 25 to permit the positive corrective However, upon movement of the actuators past full cycle position in the positive direction, switch 23 will again be closed as at this time the numeral wheels will again be in the same position in which they were when the overdraft signal occurred. Re lay 17 will, therefore, be energized again and the stopping means will be operated at the end of the single positive corrective cycle, the carriage shifted, and the division program resumed as disclosed in the aforenoted patent.

At the end of the division program, link 7252, link 733, arm 732, crank 726, and latch 725 will be restored. Thus, link 730 will be moved upwardly thereby rocking lever This movement will release bail 54 and arms 46 will be spring moved into engagement with cams 47, thereby moving numeral Wheels 1 to aligned position.

The erein described uses of the invention are illustrative only of obvious applications. The invention, therefore, is not to be restricted to the specific application herein described, but is to be restricted only as necessitated by the scope of the appended claims.

We claim:

1. The combination with a register including numeral Wheels and crawl tens transfer mechanism between said wheels; of means for establishing a light ray, a light responsive device, an optical system including a deflector element adjustable by each of said wheels upon passage through zero position in changing the sign of said register to deflect said light ray to impinge upon said light responsive device, and an electric signaling circuit controlled by said light responsive device.

2. The combination with a register including numeral wheels and crawl tens transfer mechanism between said wheels; of means for establishing a light ray, a light responsive device, an adjustable optical system including a series of deflector elements, a drive transmission operable by each of said wheels upon passage through zero position in changing the sign of said register to adjust one of said deflector elements deflect said light ray to impinge upon said light responsive device, and an electric signaling circuit controlled by said light responsive device.

3. The combination with a register including numeral wheels and crawl tens transfer mechanism between said wheels; of means for establishing a light ray, a light responsive device, a drive transmission operable by each of said wheels, a device for blocking said light ray adjustable by each drive transmission, means for impinging said light ray upon the blocking device of the highest order wheel, a light deflecting element movable with the blocking device of said highest order wheel into the path of said ray to deflect said light ray to impinge upon said light responsive device upon passage of said highest order wheel through zero position, an opening in each blocking device to permit passage of said light ray to impinge upon the blocking device of a lower order wheel upon movement of the higher order wheels to substantially zero position, a light deflecting element movable with the blocking device of said lower order Wheel into the path of said light ray to deflect said ray to impinge upon said light responsive device upon passage of said lower order wheel through zero position, and an electric signaling circuit controlled by said light responsive device.

4. The combination with a register including numeral Wheels and crawl tens transfer mechanism between said wheels; of means for establishing a light ray, a pair of light responsive devices, an adjustable optical system including a series of deflector elements, a drive transmission operable by each of said Wheels upon passage through zero position in changing the sign of said register to adjust one of said deflector elements to deflect said light ray to impinge upon one of said light responsive devices and operable upon movement of said register to zero registering position to adjust said optical system to impinge said light ray upon the other of said light responsive devices, and an electric signaling circuit controlled by each of said light responsive devices.

5. The combination with a register including numeral wheels and crawl tens transfer mechanism between said wheels; of means for establishing a light ray, a light responsive device, a gear for blocking said light ray driven in time with each of said wheels, means for impinging said light ray upon the gear of the highest order wheel, an opening in each of said gears to permit passage of said light ray to impinge upon the gear of the next lower order wheel upon movement of all of the next higher order wheels to substantially zero position, a reflector on each of said gears movable into the path of said light ray to reflect said ray upon said light responsive device upon passage of the associated wheel through zero position, and an electric signaling circuit controlled by said light responsive device.

6. The combination with a register including numeral wheels and crawl tens transfer mechanism between said wheels; of means for establishing a light ray, a gear for blocking said light ray driven in time with each of said wheels, means for impinging said light ray upon the gear of the highest order wheel, an opening in each of said gears to permit passage of said light ray to impinge upon the gear of the next lower order wheel upon movement of all of the next higher order wheels to substantially zero position, a light responsive device extending longitudinally of said gears and located at one side thereof, a reflector on each of said gears movable into the path of said light ray to reflect said ray upon said light responsive device upon passage of the associated wheel through zero position, and an electric signaling circuit controlled by said light responsive device.

7. The combination with a register including numeral wheels and crawl tens transfer mechanism between said wheels; of means for establishing a light ray, a gear for blocking said light ray driven in time with each of said wheels, means for impinging said light ray upon the gear of the highest order wheel, an opening in each of said gears to permit passage of said light ray to impinge upon the gear of the next lower order wheel upon movement of all of the higher order wheels to substantially zero position, a light responsive device located adjacent the opening of the gear of said highest order wheel, a reflecting surface on each of said gears movable into the path of said light ray to reflect said ray upon said light responsive device upon passage of the associated wheel through zero position, and an electric signaling circuit controlled by said light responsive device.

8. The combination with a register including numeral Wheels and crawl tens transfer mechanism between said wheels; of means for establishing a light ray, a gear for blocking said light ray driven in time with each of said wheels, means for impinging said light ray upon the gear of the highest order wheel, an opening in each gear to permit passage of said light ray to impinge upon the gear of the next lower order wheel upon movement of all of the higher order wheels to substantially zero position, a light responsive device located adjacent the opening of the gear of the lowest order wheel in the path of said light ray upon movement of all of said wheels to zero position, a light responsive device located adjacent the opening of the gear of the highest order wheel, a reflecting surface on each of said discs movable into the path of said light ray to reflect said ray upon the second said light responsive devices upon passage of the associated wheel through zero position, and an electric signaling circuit controlled by each light responsive device.

9. The combination with a register including numeral wheels and crawl tens transfer mechanism between said wheels; of means for establishing a light ray, a light responsive device, a pair of adjustable blocking devices, a drive transmission for driving each blocking device respectively in time with a higher and the adjacent lower order of said wheels, means for impinging said light ray upon the blocking device of said higher order wheel, an opening in the blocking device of said higher order wheel to permit passage of said light ray to impinge upon the blocking device of said lower order wheel upon movement of said higher order wheel substantially to zero registering position, a reflector movable with each blocking device into the path of said light ray upon movement of the associated wheel negatively from zero position and out of said path upon passage of said wheel negatively through a given registering position; said reflectors being operable to reflect said light my upon said light responsive device, and an electric signal circuit controlled by said light responsive device.

10. The combination with a register including numeral wheels and crawl tens transfer mechanism between said Wheels; of means for establishing a light ray, a light responsive device, a pair of adjustable blocking devices each having an opening therein, a drive transmission for driving the blocking devices respectively in time with a higher and the adjacent lower order numeral wheel, means for impinging a light ray upon the blocking device of the higher order wheel to permit passage of said ray through the opening therein upon movement of said wheel to substantially zero position to thereby impinge said ray on the blocking device of the lower order wheel, a deflecting element movable with each blocking device into the path of said light ray upon movement of the associated wheel in a given direction from zero position to a given registering position to deflect said light ray to impinge on said light responsive device and upon the aforesaid movement of the lower order wheel the tens transfer movement to said higher order wheel being operable to move the opening of the associated blocking device from the path of said light ray, and an electric signaling circuit controlled by said light responsive device.

References Cited in the file of this patent UNITED STATES PATENTS 2,052,844 Prusso et al. Sept. 1, 1936 2,448,830 Robbins et al Sept. 7, 1948 2,558,721 Allen et al. July 3, 1951 

